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What your nails reveal about your health

Woman rubbing her hands - What your nails say about your health
Brittle nails can be attributed to aging, poor moisturization or malnutrition.

Dr. Erik Stratman, a Marshfield Clinic dermatologist, discusses five things your nails may say about your health and when to see a specialist.

Yellow nails

Nail polish residue

Yellowish-orange or -brown nail discoloration commonly is caused by nail polish residue.

“Some patients present to our office concerned nail discoloration means something terrible when, in fact, it’s staining left behind from polish,” Stratman said.


More than half of patients over 60 years old experience at least one infected toenail because of fungus. This can cause irregular yellowing of the nails, particularly at the nail ends. In most cases this isn’t concerning. However, risk for other infections increase in patients with uncontrolled diabetes or leg cellulitis.

Nails can infect the skin of the feet, such as with Athlete’s feet. Little cracks in the skin of the feet from this fungus infection can allow bad bacteria to infect the legs or lead to sores that heal poorly in diabetic skin.

Yellow nail syndrome

Probably the most rare cause of discoloration. Patients with yellow nail syndrome develop thickened, curved nails that stop growing.

This can signify lung and respiratory problems and is often associated with swelling of arms and legs from accumulating fluid.

Dry, cracked or brittle nails


Dry, cracked and brittle nails are common for older people.

Poor moisturization

Just like our skin can become dry in winter or from using harsh soaps, nails can become dry and cracked from poor moisturization.

“Applying a daily white petrolatum jelly coating to the nails after soaking in water for 15-20 minutes can help reverse dry, cracked or brittle nails,” Stratman said.


Brittle nails also can be caused by poor nutrition.

“If your nails are brittle or peel, make sure your diet is healthy,” he said. “Taking a daily multivitamin including B vitamins may help.”

Use this handy tip sheet for a balanced diet with healthy portions.

Nails with white spotsWhat your nails say about your health - chart

Active life? No problem.

White spots are common on nails, especially in patients active with their hands.

Often, white spots on nails come from trauma by minor nicks and bangs not traumatic enough to cause bluish-purple bruising.

Solid white? See the doc.

If nails are solid white where half the nail is discolored horizontally, see your dermatologist or primary care doctor.

Nails with pitting

Signs of skin or hair diseases

The birthplace of the nail underneath the cuticle region is called the matrix.

When certain areas of the matrix are inflamed, pitting can occur as the nail grows.

“It can look like someone took a hammer and nail and made a little tap with it in several places on the nail,” Stratman said.

Pitting most commonly occurs with a skin disease called psoriasis, but can occur in a variety of diseases including eczema and alopecia areata.

Nails with vertical or horizontal ridges

Vertical ridges, aging

These are common with aging and typically do not typically signify health concern.

If cosmetically bothersome, buffing ridges with emery boards or nail care devices can help.

Horizontal ridges: Thumb or index fingers

When horizontal ridges occur only on the thumbs and index fingers in a series of hatch marks along the central nail, it is often due to picking, known as habit-tic nail deformity. Unconscious picking is the most common reason for horizontal ridges. 

Horizontal ridges: All nails

When horizontal ridges are present on all nails, this may represent Beau’s lines.

Beau’s lines usually are caused by physical stress, such as serious illness or chemotherapy. Sometimes severe psychological stressors cause Beau’s lines, too.

When the body is under significant physical or mental stress, it shuts down all nonessential energy expenditures in the body. The first things halted during stress are hair and nail growth.

“These deep horizontal ridges are most commonly seen in patients undergoing cycles of chemotherapy,” Stratman said. “Crash diets also can cause such lines.”

When the stress is over, the body allows nails to grow normally again, but not until there has been a horizontal indentation line of growth arrest. Usually lines are seen a month or two after resolution of the stressor, as the new nail grows.

When to see a provider

Vertical pigmented streak

The most serious nail concern is a vertical pigmented streak on a single nail.

Sometimes this occurs just from having darker skin tones, but other times atypical moles or deadly skin cancers, melanomas, arise under the nail in the matrix. This can result in a vertical pigmented streak.

Getting skin cancer where ‘the sun don’t shine’

Anyone with a vertical pigmented streak should see a provider skilled in looking at nail disease, Stratman said. Sometimes a biopsy is necessary to determine the nature of the pigmented streak.

Talk to your doctor

It is okay to seek professional advice on any nail concern. Seeing a dermatologist, podiatrist, hand specialist or other professionals skilled in management of nail disease is a good first step to getting correct information.

Find a Marshfield Clinic doctor.

10 responses to “What your nails reveal about your health”

  1. Kristy Loosier

    My index finger on my left hand has turned an orange color. Also along side has turned into a black streak. What could be the cause of this?

    1. Jacob Zipperer

      Hi, Kristy.

      Thanks for reaching out. Unfortunately, we cannot provide individualized health advice on this forum.

      We recommend contacting your doctor to address your health concerns. He or she is most aware of your medical history.

      If you are a Marshfield Clinic patient, you can message a provider directly through My Marshfield Clinic: https://www.marshfieldclinic.org/mymarshfieldclinic


  2. Audrey

    A couple of months ago, I caught my thumb nail in a fitted sheet while making the bed. My thumb nail was pulled away from the nail bed and, while it hurt like heck, it never bled. Since then, it seems like my hyponychium has grown thicker – to the point that it has pushed my nail away from the bed far enough to distort the curve of the nail. Also, the skin on my fingertip is extra dry and occasionally cracks. I expected that any damage would have grown out by now but it doesn't seem to be getting any better. I tried to attach a photo but could not. Do you think something else may be going on? Does it sound like anything else you've seen or heard of?

    1. Kirsten Shakal, Shine365 Editor

      Hi, Audrey. Thank you for reaching out. Though we cannot provide individualized medical advice, Dr. Stratman was able to provide a response with information on nail injury and how to care for it going forward:

      "A damaged nail does not always fall off immediately. Sometimes the new nail slowly grows and replaces the new nail, but this typically takes 6 months for an entire new nail to replace. It’s possible the thickening represents the old nail being shoved upward by the new nail. It is unclear why the end is cracking and dry, though that can happen just with daily exposure to cleaning supplies or colder weather. If the change is still present after 6 months from the initial injury, I encourage you to have the nail examined by your medical provider. In the meantime, use some good moisturizing with white petrolatum (Vaseline) twice daily to the thumb tip to see if this helps the scaling and cracking."

      Thank you for reading Shine365. -Kirstie

  3. Donna K. Raubal

    The nails on my left hand are curving downward and seem to be getting more and more curved. At first it was just the two middle fingers but now all but the thumb nail are involved. They curve down in the middle and up at the sides. I am 81 years old and wonder if this is part of the aging process. Thank you.

    1. Kirsten Shakal, Shine365 Editor

      Thank you for your question, Donna. I did share your comment with Dr. Stratman. Though we cannot provide individualized medical advice on this forum, he did share with me this:

      "Many changes can occur to the shape and texture of nails as part of the normal aging process. This usually involves a series of lines going down the middle, like a washboard. Sometimes, when nails are curved in the shape of a spoon (dipped in the middle) or curved downward over the end of your nail at the fingertip, it can be a sign of a medical disorder. In these instances, it's important for your doctor to evaluate further looking for nutritional or endocrine disorders. If it is more like a groove (like a downturned ditch in a line down the center of your nail), that can be from a nail bed growth or nail formation disorder."

      Dr. Stratman suggests bringing your concerns to your primary care provider during your next routine visit. If you are a Marshfield Clinic patient, you can contact your care team via My Marshfield Clinic: https://www.marshfieldclinic.org/mymarshfieldclinic.

      I hope this helps, and thank you for reading Shine365. -Kirstie

  4. Lee V

    When I wear nail polish my fingernnails get soft and split. What causes this and what can I do to enable me to wear polish

    1. Kirsten Shakal, Shine365 Editor

      Hi, Lee. Sorry for the delay in responding. I wanted to share your concerns with an expert first.

      We can't speak to your specific concerns as we cannot provide individualized medical advice on this forum. However, I talked to Dr. Stratman about nail splitting in general and he shared, "There are many causes of nail splitting, but nail polish itself isn't typically a cause. Drying out of nails may be at play. I usually recommend a routine for one month of soaking fingertips in water and then applying petroleum jelly to the nails overnight. If that doesn't strengthen the nails, a person should discuss their concerns with a provider."

      I hope this helps. -Kirstie

  5. Vicky Jenks

    I have arthritis both osteoporosis and rheumatoid. I I have white vertical lines,. My nails chip frequently,never able to grow long. Crack and peel and break when I have fingernail polish on. I'm being stopped of my sq. ENBREL and willing be starting Cemza, sq. I have been on p.o. Methotrexate for a long time. Any ideas to help me with my nails? Thank you. Found this article very informatiive.

    1. Kirsten Shakal, Shine365 Editor

      Hi, Vicky. We cannot give individualized health advice on this forum.

      You can find a doctor to address your specific concerns regarding your nail health or create and use your My Marshfield Clinic's secure messaging to safely send questions to your care team:
      Find a doctor: https://www.marshfieldclinic.org/Doctors
      My Marshfield Clinic: https://www.marshfieldclinic.org/mymarshfieldclinic

      Thank you for reading. -Kirstie

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